Vince Cable argues here that the tech giants need to be broken up, arguing that their size is a threat to welfare. He argues that these companies represent new forms of monopoly, and are able to hide behind the fact that ostensibly they offer 'free' services.

He argues that they should be broken up, and that people should be given more property rights over their own data - an application of an essential feature of market economies. I can foresee problems with this - it will be difficult for people to 'value' their data and thus, they won't be able to allocate resources accordingly, by selling aspects of it at the appropriate price, for example.

All in all, a classic microeconomic dilemma.

September 2018 update - a short video from the Economist